This invention relates to novel carbamoylphosphonates and their use as brush control agents. The use of various carbamoylphosphonates for control of plant growth is known in the art. For example, U.S. Pat. No. 3,627,507 and Offenlegungschrift No. 2,040,367 relate to the use of carbamoylphosphonates for plant growth control. However, neither of these references disclose the compounds of this case, nor do the references disclose a procedure by which the compounds of this invention can be made.